#include<stdio.h>
int main()
{
    int n,i;
    scanf("%d",&n);
    double average[n-1];
    double fn=0.0;
    for(i=0;i<n;i++)
    {
       scanf("%lf",&average[i]);
       fn=fn+average[i];
      
    }
    printf("%.2lf",fn/n);
    return 0;

}